Co-occurrence of extremes in surface ozone, particulate matter, and temperature over eastern North America
Significance Exposure to extreme temperatures and high levels of the pollutants ozone and particulate matter poses a major threat to human health. Heat waves and pollution episodes share common underlying meteorological drivers and thus often coincide, which can synergistically worsen their health impacts beyond the sum of their individual effects. Furthermore, there is evidence that pollution episodes and heat waves will worsen under future climate change, making it imperative to understand the nature of their co-occurrence. In this paper, using 15 years of surface observations over the eastern United States and Canada, we show that the extremes cluster together in often overlapping large-scale episodes, and that the largest episodes have the hottest temperatures and highest levels of pollution.